1. Field of the Invention:
The present invention pertains to an electromagnetic solenoid, and more particularly to a compact solenoid for slowly driving a light-weight object with substantially no impact upon hitting a surface at the end of its travel.
2. Description of the Prior Art:
An electromagnetic solenoid of the prior art is arranged so that a plunger is inserted within the core of an electromagnetic coil to be operative so that this plunger is moved forwardly and backwardly with the supply and suspension of electric current to the coil. It is usual that the time required for the plunger to complete one whole stroke is a matter of about a milli-second. Efforts have been made in the past for a further reduction of this length of time of stroke.
On the other hand, it is known that oil pressure as well as air pressure apparatus are widely utilized as a driving means where quick movement is not required. Such an apparatus invariably is considerably complicated in its structure and accordingly tends to be large in size and requires a great deal of labor in its maintenance.
In order to solve these problems of known driving means which do not need quick driving, and to obtain a compact size solenoid for slow driving, especially a light-weight object the inventor has made an extensive research in developing a new type of solenoid as the driving means for accomplishing these objects and has succeeded in attaining them.